Interior Secretary Ken Salazar said Wednesday that he will quit his post in March after four tumultuous years overseeing oil drilling, recreation, grazing and other activities on federal lands and waters.

For most of that tenure, Salazar tangled with the energy industry. That tension was on display as Salazar presided over the reorganization of government agencies that police offshore drilling in the wake of the 2010 Gulf of Mexico oil spill.

Under Salazar's watch, the Minerals Management Service was dismantled and replaced with three agencies separately responsible for collecting revenue from offshore energy development, leasing federal waters and overseeing the activity.

"We have undertaken the most aggressive oil and gas safety and reform agenda in U.S. history, raising the bar on offshore drilling safety, practices and technology and ensuring that energy development is done in the right way and in the right places," Salazar said in a statement Wednesday.

"Today, drilling activity in the gulf is surpassing levels seen before the spill, and our nation is on a promising path to energy independence."

Salazar drew attention for his tough talk during the spill, declaring that the Obama administration would "keep the boot on the neck of British Petroleum."

He imposed a five-month ban on most deep-water exploration while oil gushed from BP's Macondo well and regulators developed new mandates in response to the disaster.

As interior secretary, Salazar made renewable energy development on public lands and waters a priority. Before he took office, no large-scale solar projects on federal lands had been approved. But his Interior Department green-lighted 18 of them, the result of an initiative meant to streamline permitting of those projects.

Since 2009, the department has authorized 34 solar, wind and geothermal energy projects.

Oil and gas industry leaders said Salazar focused too much on spurring renewable energy while overlooking traditional fossil fuel development. Energy companies and their allies have complained it takes far longer to get permits to drill on federal lands than on state and private tracts.

Salazar's March exit lets President Obama focus first on filling other open Cabinet posts, including those of the secretary of state, Treasury secretary, labor secretary and environmental protection administrator.

In replacing Salazar, Obama could tap a lawmaker or governor from a Western state.

Obama also could choose to elevate Deputy Secretary David Hayes, who has spearheaded a commission on Arctic energy development and been heavily involved in efforts to improve the safety of offshore drilling.